The application discloses an OPGW (Optical Fiber Composite Overhead Ground Wire) terminal reserved-cable device of an ultrahigh-voltage transformer substation and the device prevents a problem of inter-turn discharge electric-corrosion strand breakage of an optical cable, which exists in a wound optical cable and is caused by inter-turn induction voltages and prevents a problem of galvanic corrosion strand breakage generated by contact of the optical cable and a seizing iron wire and thus the device is safe and reliable and beautiful. The device includes a nonmetal inner fork and nonmetal outer forks. The nonmetal inner fork is cross-shaped. The nonmetal outer forks are arranged on four arms of the nonmetal inner fork and form four grooves with the nonmetal inner fork. An OPGW terminal reserved cable is wound in the four grooves. A plurality of cable-limiting distance adjustment holes are uniformly distributed in the arms of the nonmetal inner fork. A plurality of cable-limiting distance adjustment holes are arranged in nonmetal outer forks, corresponding to the plurality of cable-limiting distance adjustment holes in the nonmetal inner fork. Fasteners are inserted into the cable-limiting distance adjustment holes so that the OPGW terminal reserved cable in the grooves is fixed.